About Lapse Rate

The Dry Adiabatic Lapse Rate and the Saturated Adiabatic Lapse Rate

Weather Balloon
Aerographers Mate 3rd Class Robert Mason of Chicago, IL, releases a weather balloon from the fantail of the USS Harry S. Truman September 26, 1999. Getty Images

As a hypothetical parcel of air cools as it rises in the atmosphere and warms as it descends in the atmosphere. This cooling and warming of the air is known as the lapse rate. There are two primary types of lapse rate - the dry adiabatic lapse rate and the wet or saturated adiabatic lapse rate.

Dry Adiabatic Lapse Rate

Saturated Adiabatic Lapse Rate

If you're having trouble thinking about a parcel of air rising, think of a invisible balloon of air rising. As it rises, it cools as it expands. If it begins to descend it will compress and the temperature will increase.